Quantum phase measurement and Gauss sum factorization of large integers in a superconducting circuit

Abstract

We study the implementation of quantum phase measurement in a superconducting circuit, where two Josephson phase qubits are coupled to the photon field inside a resonator. We show that the relative phase of the superposition of two Fock states can be imprinted in one of the qubits. The qubit can thus be used to probe and store the quantum coherence of two distinguishable Fock states of the single-mode photon field inside the resonator. The effects of dissipation of the photon field on the phase detection are investigated. We find that the visibilities can be greatly enhanced if the Kerr nonlinearity is exploited. We also show that the phase measurement method can be used to perform the Gauss sum factorization of numbers ($\ge 10^4$) into a product of prime integers, as well as to precisely measure both the resonator's frequency and the nonlinear interaction strength. The largest factorizable number is mainly limited by the coherence time. If the relaxation time of the resonator were to be $\sim 10$ $\mu$s ($\sim 1$ ms), then the largest factorizable number can be $\ge 10^{4}N$ ($\ge 10^{7}N$), where $N$ is the number of photons in the resonator.

13 pages, 5 figures

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Cited by in corpus (6)

• Microwave photonics with superconducting quantum circuits
• Computing prime factors with a Josephson phase qubit quantum processor
• Factorization of numbers with Gauss sums: I. Mathematical background
• Steady-state entanglement in a double-well Bose-Einstein condensate through coupling to a superconducting resonator
• Ghost factors in Gauss-sum factorization with transmon qubits
• An Efficient Deterministic Quantum Algorithm for the Integer Square-free Decomposition Problem